🔥 8 Hours to Java Mastery: Collections, Streams & More

🚀 Introduction

I recently completed an 8-hour intensive YouTube tutorial on the Java Collections Framework and Stream API (watch it here). This session not only deepened my understanding but also clarified several advanced topics. In this blog, I’m sharing my notes, key takeaways, and runnable code examples to help you learn faster.

🧰 What’s Covered in the Video?

• Collection Interfaces (, , , )

• Implementation classes (, , , etc.)

• Java 8 Features: Lambda Expressions, Stream API, and Method References

• usage and best practices

• Queues: , , as Queue

• Functional programming & best practices

• Parallel streams for performance optimization

💡 Stream API – A Game Changer

Java 8 introduced the Stream API, enabling functional-style operations on data.

🧪 Code Sample:

🧠 Key Concepts:

• Intermediate ops: , , ,

• Terminal ops: , , ,

• Method References: cleaner syntax than lambdas

• Parallel Streams: fast on large datasets, use with caution

🧱 Java Collections Deep Dive

🔸 Interfaces:

• , , , ,

🔸 Popular Implementations:

• ArrayList: dynamic array, fast random access

• LinkedList: efficient insert/delete, used as both list and queue

• HashSet: no duplicates, unordered

• TreeMap: sorted key-value pairs

• PriorityQueue: queue with natural/custom ordering

🔸 Enum Usage:

Enums are ideal for fixed sets of constants. You’ll also see them used in statements and for grouping configuration types in large-scale projects.

🧾 What I Found Most Interesting

• Method References like cleaned up my code significantly

• Parallel Streams blew my mind with performance tricks

• I now prefer for role management or status control

• I learned how to implement custom for sorting objects

• Got hands-on with and

📌 Final Thoughts

This course was more than just syntax—it was about clean coding, choosing the right data structure, and writing efficient logic using modern Java features. I highly recommend every Java developer bookmark this resource.

📚 References

This article is based on my learning from the Java Collections & Streams by Engineering Digest. I highly recommend watching the full 8-hour tutorial for in-depth coverage.

💼 Let’s Connect

If you're a backend developer or Java learner, feel free to share your thoughts or ask me for more code samples on LinkedIn.